BACKGROUND:Pneumococcal polysaccharide vaccine (PPV) is used in children at high risk of IPD. PPV is generally not considered to induce immunologic memory, whereas pneumococcal conjugate vaccines (PCVs) elicit protective antibody responses in infants and induce immunologic memory. Little is known about the characteristics of immune responses to PCV in children who previously received PCV and PPV in series.

OBJECTIVE:To characterize immune responses to 13-valent pneumococcal CRM197 conjugate vaccine (PCV13; serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) in children vaccinated in infancy with 9-valent pneumococcal-meningococcal C-CRM197 conjugate combination vaccine (PCV9-MnCC), followed by a toddler dose of PCV9-MnCC or 23-valent pneumococcal polysaccharide vaccine (PPV23).

METHODS:Children (n=89) who received PCV9-MnCC in infancy and PPV23 or PCV9-MnCC at age 12 months in a previous (2002-2003) study were vaccinated at age 7.5 years with PCV13; groups PPV23/PCV13 (n=50) and PCV9/PCV13 (n=39). Immunoglobulin (Ig)G antibodies, avidity, and opsonophagocytic activity (OPA) were measured before and at 1 and 4 weeks postvaccination.

RESULTS:One week postvaccination, IgG levels increased significantly for all serotypes in both groups, and>97% of vaccinees achieved IgG≥0.35μg/ml 4 weeks after PCV13 vaccination. The PCV9/PCV13 group had higher IgG responses compared with the PPV23/PCV13 group. The upper limits of the 95% confidence intervals of the PPV23/PCV13:PCV9/PCV13 IgG geometric mean concentration ratios were<1.0 for serotypes 1, 4, 5, 9V, 18C, and 23F at 1 week. OPA and avidity results supported these findings.

CONCLUSIONS:PPV23 vaccination of toddlers may compromise subsequent responses to pneumococcal conjugate vaccines. The clinical relevance of this finding is unclear.

BACKGROUND:We estimated the vaccine effectiveness (VE) of tetanus-diphtheria-acellular pertussis vaccine (Tdap) for preventing pertussis among adolescents during a statewide outbreak of pertussis in Wisconsin during 2012.

METHODS:We used the population-based Wisconsin Immunization Registry (WIR) to construct a cohort of Wisconsin residents born during 1998-2000 and collect Tdap vaccination histories. Reports of laboratory-confirmed pertussis with onset during 2012 were matched to WIR clients. Incidence rate ratios (IRRs) of pertussis and Tdap VE estimates [(1 - IRR)*100%], by year of Tdap vaccine receipt and brand (Boostrix/Adacel), were estimated using Poisson regression.

RESULTS:Tdap VE decreased with increasing time since receipt, with VEs of 75.3% (95% confidence interval [CI], 55.2%-86.5%) for receipt during 2012, 68.2% (95% CI, 60.9%-74.1%) for receipt during 2011, 34.5% (95% CI, 19.9%-46.4%) for receipt during 2010, and 11.9% (95% CI, -11.1% to 30.1%) for receipt during 2009/2008; point estimates were higher among Boostrix recipients than among Adacel recipients. Among Tdap recipients, increasing time since receipt was associated with increased risk, and receipt of Boostrix (vs Adacel) was associated with decreased risk of pertussis (adjusted IRR, 0.62 [95% CI, .52-.74]).

CONCLUSIONS:Our results demonstrate waning immunity following vaccination with either Tdap brand. Boostrix was more effective than Adacel in preventing pertussis in our cohort, but these findings may not be generalizable to adolescent cohorts that received different diphtheria-tetanus-acellular pertussis vaccines (DTaP) during childhood and should be further examined in studies that include childhood DTaP history.

A 7-month-old boy became difficult to arouse, was limp and had blue extremities 8 hours after immunization with intravenous poliovirus, diphtheria-tetanus toxoids-acellular pertussis, Haemophilus influenzae type b-hepatitis B virus and pneumococcal vaccines. The hypotonic-hyporesponsive episode had resolved by the time the infant was seen in an emergency department 1 hour later. The report describes hypotonic-hyporesponsive episode, encourages reporting of vaccine-associated adverse events and discusses prognosis and implications for subsequent immunization.